Seroprevalence of rubella antibodies and determinants of susceptibility to rubella in a cohort of pregnant women in Canada, 2008–2011

Long term control of rubella and congenital rubella syndrome relies on high population-level immunity against rubella, particularly among women of childbearing age. In Canada, all pregnant women should be screened so that susceptible new mothers can be offered vaccination for rubella before discharge. This study was undertaken to estimate rubella susceptibility in a cohort of pregnant women in Canada and to identify associated socio-economic and demographic factors. Biobanked plasma samples were obtained from the Maternal-Infant Research on Environmental Chemicals (MIREC) study, in which pregnant women were recruited between 2008 and 2011. Socio-demographic characteristics and obstetric histories were collected. Second trimester plasma samples (n = 1,752) were tested for rubella-specific IgG using an in-house enzyme-linked immunosorbent assay. The percentage of women with IgG titers <5 IU/mL, 5–10 IU/mL, and 10 IU/mL were 2.3%, 10.1%, and 87.6%, respectively. Rates of seronegativity, defined as <5 IU/mL, were 3.1% in women who had no previous live birth and 1.6% in women who had given birth previously. Among the latter group, seronegativity was higher in women with high school education or less (adjusted OR (aOR) 5.93, 95% CI 2.08–16.96) or with a college or trade school diploma (aOR 3.82, 95% CI 1.45–10.12), compared to university graduates, and those born outside Canada (aOR 2.60, 95% CI 1.07–6.31). In conclusion, a large majority of pregnant women were found to be immune to rubella. Further research is needed to understand inequalities in vaccine uptake or access, and more effort is needed to promote catch-up measles-mumps-rubella vaccination among socioeconomically disadvantaged and immigrant women of childbearing age

Associations between Attention-Deficit/Hyperactivity Disorder and various eating disorders: A Swedish nationwide population study using multiple genetically informative approaches

Background Although attention-deficit hyperactivity/impulsivity disorder (ADHD) and eating disorders (EDs) frequently co-occur, little is known about the shared etiology. In this study we comprehensively investigated the genetic association between ADHD and various EDs, including anorexia nervosa (AN) and other EDs (OED, including bulimia nervosa [BN]). Methods We applied different genetically informative designs to register-based information of a Swedish nationwide population (N=3,550,118). We first examined the familial co-aggregation of clinically diagnosed ADHD and EDs across multiple types of relatives. We then applied quantitative genetic modeling in full-sisters and maternal half-sisters to estimate the genetic correlations between ADHD and EDs. We further tested the associations between ADHD polygenic risk scores (PRS) and ED symptoms, and between AN PRS and ADHD symptoms, in a genotyped population-based sample (N=13,472). Results Increased risk of all types of EDs was found in individuals with ADHD (any ED: OR [95% CI]=3.97 [3.81-4.14], AN: 2.68 [2.15-2.86], OED: 4.66 [4.47-4.87], BN: 5.01 [4.63-5.41]) and their relatives compared to individuals without ADHD and their relatives. The magnitude of the associations reduced as the degree of relatedness decreased, suggesting shared familial liability between ADHD and EDs. Quantitative genetic models revealed stronger genetic correlation of ADHD with OED (0.37 [0.31-0.42]) than with AN (0.14 [0.05-0.22]). ADHD PRS correlated positively with ED symptom measures overall and sub-scales “drive for thinness” and “body dissatisfaction”, despite small effect sizes. Conclusions We observed stronger genetic association with ADHD for non-AN EDs than AN, highlighting specific genetic correlation beyond a general genetic factor across psychiatric disorders

Burden and deaths associated with vaccine preventable diseases in Canada, 2010-2014

ObjectiveTo describe the recent trends in the burden of disease and mortalityassociated with vaccine preventable diseases (VPDs).IntroductionVaccination is one of the most successful public healthinterventions. Despite this, there are a variety of reasons that VPDscontinue to be seen in developed countries such as Canada. Thisanalysis describes the recent trends in the burden of disease andmortality associated with VPDs for which publicly funded vaccinationprograms for infants or children are implemented across the countryand for which national surveillance data are available.MethodsSurveillance data on VPDs were obtained from the CanadianNotifiable Disease Surveillance System. Population and death datawere obtained from Statistics Canada. Death data were only availableto 2012. In total, 11 VPDs have been included in the analysesnamely tetanus, diphtheria, pertussis, polio, haemophilus influenza(Hi), measles, mumps, rubella, congenital rubella syndrome (CRS),invasive meningococcal disease (IMD), invasive pneumococcaldisease (IPD). Exclusion of non-vaccine preventable serotypes fromeither data source was not possible. Analyses included incidence rate,proportion, mortality rate and risk ratio.ResultsSurveillance data indicate that from 2010 to 2014, an average of6,020 cases of VPDs were reported annually, representing an averageannual crude incidence rate of 17.3 cases per 100,000 population.VPDs accounting for the largest proportion of reported cases includeIPD (54.4%) and pertussis (29.6%). Age groups most affected includechildren less than 1 year of age (92.6 cases per 100,000) and childrenbetween 1 and 4 years of age (36.0 cases per 100,000). Age groupsleast affected include adults between 20 and 24 years old (6.9 casesper 100,000 population) and between 25 and 29 years old (7.3 casesper 100,000 population). Age groups affected differed by VPD.Death data indicate that from 2010 to 2012, VPDs accountingfor the largest proportion of deaths across all ages include IPD(58.2%), Hi (16.3%) and IMD (15.3%). Youth aged 19 years andunder accounted for 26.1% of VPDs deaths (mortality rate of 0.17 per100,000 population). Children less than one year old have the highestmortality rate due to VPDs (2.0 per 100,000 population) and were26.9 times more likely to die from VPDs compared to children between1 and 19 years of age. Adults aged 20 years and older accounted for73.9% of VPD deaths (mortality rate of 0.14 per 100,000 population).A high mortality rate was also seen in adults 60 year old and over(0.3 per 100,000 population); adults 60 years old and over were more2.6 times more likely to die from VPDs compared to adults between20 and 59 years old.ConclusionsThe results of routine Canadian surveillance data suggest thatdespite high vaccine coverage rates generally seen in developedcountries such as Canada, a possible preventable burden of illnessdue to VPDs still occurs across all age groups. Consideration ofVPDs as a whole allows a real appreciation of the burden and deathsassociated with VPDs in general. The analysis has shown that whilethe incidence rates are highest among children 4 years old andyounger, mortality due to VPDs continues to occur and primarilyaffects infants and elderly. Due to the asymptomatic nature of someVPDs and data limitations, reported cases are likely underestimatesof the true burden

Burden and deaths associated with vaccine preventable diseases in Canada, 2010-2014

ObjectiveTo describe the recent trends in the burden of disease and mortalityassociated with vaccine preventable diseases (VPDs).IntroductionVaccination is one of the most successful public healthinterventions. Despite this, there are a variety of reasons that VPDscontinue to be seen in developed countries such as Canada. Thisanalysis describes the recent trends in the burden of disease andmortality associated with VPDs for which publicly funded vaccinationprograms for infants or children are implemented across the countryand for which national surveillance data are available.MethodsSurveillance data on VPDs were obtained from the CanadianNotifiable Disease Surveillance System. Population and death datawere obtained from Statistics Canada. Death data were only availableto 2012. In total, 11 VPDs have been included in the analysesnamely tetanus, diphtheria, pertussis, polio, haemophilus influenza(Hi), measles, mumps, rubella, congenital rubella syndrome (CRS),invasive meningococcal disease (IMD), invasive pneumococcaldisease (IPD). Exclusion of non-vaccine preventable serotypes fromeither data source was not possible. Analyses included incidence rate,proportion, mortality rate and risk ratio.ResultsSurveillance data indicate that from 2010 to 2014, an average of6,020 cases of VPDs were reported annually, representing an averageannual crude incidence rate of 17.3 cases per 100,000 population.VPDs accounting for the largest proportion of reported cases includeIPD (54.4%) and pertussis (29.6%). Age groups most affected includechildren less than 1 year of age (92.6 cases per 100,000) and childrenbetween 1 and 4 years of age (36.0 cases per 100,000). Age groupsleast affected include adults between 20 and 24 years old (6.9 casesper 100,000 population) and between 25 and 29 years old (7.3 casesper 100,000 population). Age groups affected differed by VPD.Death data indicate that from 2010 to 2012, VPDs accountingfor the largest proportion of deaths across all ages include IPD(58.2%), Hi (16.3%) and IMD (15.3%). Youth aged 19 years andunder accounted for 26.1% of VPDs deaths (mortality rate of 0.17 per100,000 population). Children less than one year old have the highestmortality rate due to VPDs (2.0 per 100,000 population) and were26.9 times more likely to die from VPDs compared to children between1 and 19 years of age. Adults aged 20 years and older accounted for73.9% of VPD deaths (mortality rate of 0.14 per 100,000 population).A high mortality rate was also seen in adults 60 year old and over(0.3 per 100,000 population); adults 60 years old and over were more2.6 times more likely to die from VPDs compared to adults between20 and 59 years old.ConclusionsThe results of routine Canadian surveillance data suggest thatdespite high vaccine coverage rates generally seen in developedcountries such as Canada, a possible preventable burden of illnessdue to VPDs still occurs across all age groups. Consideration ofVPDs as a whole allows a real appreciation of the burden and deathsassociated with VPDs in general. The analysis has shown that whilethe incidence rates are highest among children 4 years old andyounger, mortality due to VPDs continues to occur and primarilyaffects infants and elderly. Due to the asymptomatic nature of someVPDs and data limitations, reported cases are likely underestimatesof the true burden

Spatiotemporal epidemiology of substance-related accidental acute toxicity deaths in Canada from 2016 to 2017

Abstract Objectives In Canada, substance-related accidental acute toxicity deaths (AATDs) continue to rise at the national and sub-national levels. However, it is unknown if, where, when, and to what degree AATDs cluster in space, time, and space–time across the country. The objectives of this study were to 1) assess for clusters of AATDs that occurred in Canada during 2016 and 2017 at the national and provincial/territorial (P/T) levels, and 2) examine the substance types detected in AATD cases within each cluster. Methods Two years of person-level data on AATDs were abstracted from coroner and medical examiner files using a standardized data collection tool, including the decedent's postal code and municipality information on the places of residence, acute toxicity (AT) event, and death, and the substances detected in the death. Data were combined with Canadian census information to create choropleth maps depicting AATD rates by census division. Spatial scan statistics were used to build Poisson models to identify clusters of high rates (p < 0.05) of AATDs at the national and P/T levels in space, time, and space–time over the study period. AATD cases within clusters were further examined for substance types most present in each cluster. Results Eight clusters in five regions of Canada at the national level and 24 clusters in 15 regions at the P/T level were identified, highlighting where AATDs occurred at far higher rates than the rest of the country. The risk ratios of identified clusters ranged from 1.28 to 9.62. Substances detected in clusters varied by region and time, however, opioids, stimulants, and alcohol were typically the most commonly detected substances within clusters. Conclusion Our findings are the first in Canada to reveal the geographic disparities in AATDs at national and P/T levels using spatial scan statistics. Rates associated with substance types within each cluster highlight which substance types were most detected in the identified regions. Findings may be used to guide intervention/program planning and provide a picture of the 2016 and 2017 context that can be used for comparisons of the geographic distribution of AATDs and substances with different time periods

Laboratory characterization of invasive Haemophilus influenzae isolates from Nunavut, Canada, 2000–2012

Background: With invasive Haemophilus influenzae serotype b (Hib) disease controlled by vaccination with conjugate Hib vaccines, there is concern that invasive disease due to non-serotype b strains may emerge. Objective: This study characterized invasive H. influenzae (Hi) isolates from Nunavut, Canada, in the post-Hib vaccine era. Methods: Invasive H. influenzae isolates were identified by conventional methods at local hospitals; and further characterized at the provincial and federal public health laboratories, including detection of serotype antigens and genes, multi-locus sequence typing and antibiotic susceptibility. Results: Of the 89 invasive H. influenzae cases identified from 2000 to 2012, 71 case isolates were available for study. There were 43 serotype a (Hia), 12 Hib, 2 Hic, 1 Hid, 1 Hie, 2 Hif and 10 were non-typeable (NT). All 43 Hia were biotype II, sequence type (ST)-23. Three related STs were found among the Hib isolates: ST-95 (n=9), ST-635 (n=2) and ST-44 (n=1). Both Hif belonged to ST-124 and the 2 Hic were typed as ST-9. The remaining Hid (ST-1288) and Hie (ST-18) belonged to 2 separate clones. Of the 10 NT strains, 3 were typed as ST-23 and the remaining 7 isolates each belonged to a unique ST. Eight Hib and 1 NT-Hi were found to be resistant to ampicillin due to β-lactamase production. No resistance to other antibiotics was detected. Conclusion: During the period of 2000–2012, Hia was the predominant serotype causing invasive disease in Nunavut. This presents a public health concern due to an emerging clone of Hia as a cause of invasive H. influenzae disease and the lack of published guidelines for the prophylaxis of contacts. The clonal nature of Hia could be the result of spread within an isolated population, and/or unique characteristics of this strain to cause invasive disease. Further study of Hia in other populations may provide important information on this emerging pathogen. No antibiotic resistance was detected among Hia isolates; a small proportion of Hib and NT-Hi isolates demonstrated resistance to ampicillin due to β-lactamase production